• +44 (0)207 491 4777
  • contact@gcslab.co.uk
  • 30 New Bond Street, London W1S 2RN


We welcome you Monday to Friday from 9.30am to 4.30pm for submission and collection of your gemstones and jewellery.


Gemmological Certification Services (GCS) is a reputable independent gemmological laboratory that specializes in the identification and certification of diamonds, gemstones, and pearls. We proudly collaborate with Claude Bernard University in Lyon, France.

Within the UK, we hold the leading position as a gem lab for determining the origin of coloured gemstones, identifying synthetic coloured gemstones and lab-grown diamonds, distinguishing between natural and cultured pearls, and detecting clarity enhancements and heat treatments in sapphire, ruby, emerald, and diamond.


We understand the importance of adhering to the practices and protocols of other international laboratories. That’s why we utilise advanced testing methods such as FTIR, Raman, XRF, Digital microradiography, and UV-VIS-NIR spectrometry to meet the current challenges prevalent in the industry.

We firmly believe that ensuring the accuracy of our testing results requires collective analysis. Therefore, all our certificates feature the signatures of at least two of our gemmologists, guaranteeing the highest levels of precision.

We take great pride in offering our clients services they can trust.

Verify the authencity of a GCS report